The objectives of this project are: (1) to investigate the activity of specific chemotherapeutic agents in advanced prostatic cancer, (2) to determine if sequential therapy with these agents is useful clinically, (3) to determine their therapeutic effectiveness against and in combination with current standard therapy, and (4) to determine the predictive value of various in vitro evaluations of chemotherapeutic agents. Seven separate protocols have been developed. Six are currently operative, but patient entry into Protocol 100 ended in June of 1975, while entry for Protocol 200 ended on April 2, 1976. In Protocol 300, eligible patients are randomized into one of three treatment groups: (1) DTIC, 200 mg/sqm I.V. the first five days out of 26 days with cycles repeated, (2) Procarbazine, 100 mg/sqm orally daily for the first three weeks out of every six weeks with cycles repeated, or (3) cyclophosphamide, 1 mg/sqm intravenously every three weeks. In Protocol 400, patients who have had extensive irradiation or prior cytotoxic treatment are randomized into two treatment groups: (1) Estracyt, 600 mg/sqm p.o. daily in three divided doses plus Leo 1031, 25 mgm per day, or (2) Leo 1031, 25 mgm per day. In Protocol 500, patients are randomized to one of three treatment groups: (1) Cytoxan, 1 mg/sqm I.V. every three weeks plus Estracyt, 600 mg/sqm p.o. daily in three divided doses, (2) Cytoxan, 1 mg/sqm I.V. every three weeks plus diethylstilbestrol, 1 mgm t.i.d., p.o., or (3) diethylstilbestrol, 1 mgm t.i.d., p.o. or orchiectomy. In Protocol 600, patients are randomized to one of three treatment groups: (1) diethylstilbestrol, 1 mgm t.i.d., (2) diethylstilbestrol, 1 mgm t.i.d. plus Cytoxan, 1 mg/sqm p.o. daily. Protocol 700, which will be activated in the near future, will also randomize patients into three treatment groups: (1) hydroxyurea, 80 mg/sqm p.o. every three days, (2) MethylCCNU, 175 mg/sqm p.o. every six weeks, or (3) Cytoxan, 1 mg/sqm I.V. every three weeks. All patients are treated for a minimum of twelve weeks, at which time if progression occurs, crossover to alternate agents is done. If further progression occurs after crossover, patients are tr (Text Truncated - Exceeds Capacity)